The Ineffability of Qualia

When we communicate with each other to convey experiences and ideas, how does the information actually transfer from one mind to another? For that matter, how does a word hold meaning for us?

A common solution to this problem goes as follows: Words have no intrinsic semantic content. They instead evoke in the listener memories which are associated with the words for them. If the experiences in the listener's mind are sufficiently close to those associated with the same words in the mind of the speaker, then the message is reasonably well reconstructed in the listener's mind. This helps to explain why cultural differences, for example, can lead to misunderstandings.

If the listener doesn't understand one of the words, this means that they do not have a mental association for the word, and are thus unable to reconstruct the message in their mind. For example, lets imagine I'm describing what it is like to walk in Paris in May. Suppose this is an experience I've actually had and I want to relate it to you. Now, imagine you had never heard of Paris. I would have to resort to explaining that it was the capital city of France, and perhaps a bit about the history and geography of the place.

Since you know what cities are, and I've given the other background information in a way that you understand, you can now get some level of understanding from my pleasant stroll. However, you'd clearly not have as good an understanding of my story as someone who had also strolled in Paris in, say July.

Furthermore, if you didn't understand what a city was from first-hand experience, and I had to explain that, in the end your understanding of my anecdote could not possibly be as accurate as that of someone who knows about cities in advance, but not specifically about Paris.

Then how can a word be defined usefully using other words? The answer, of course, is that the words used in the definition must themselves evoke an association in the listener's mind. If that is not the case, then the the words comprising the definition must in turn be defined using words that for which the listener has an association.

So what constitutes the mental representation of these associations? This is arguably the definitive problem of epistemology. I will not attempt to answer it here. However, I will characterize the bounds within which the answer must lie. If you accept that information from the universe reaches our consciousness via our senses, then the bounds are pretty clear: our knowledge of the universe must be composed of information which reaches our mind via our senses. The alternative to accepting this premise is either outright solipsism or belief in some supernatural transmission of information, both of which I'm confident are excluded by my intended audience.

The required atomic units of meaning which are universally shared are called "qualia". This is a plural term whose singular is "quale". I've chosen to introduce this term based on the function it holds within this philosophical framework (rather than describing its attributes) very deliberately. This is because many erroneous attributes have been ascribed to qualia, and many cited examples of qualia are actually higher order concepts composed of numerous qualia.

Now a corollary of this solution to the problem is that qualia themselves are ineffable. That is, if you don't know what it is like to experience colour, for example, no amount of verbal description will really allow you to reconstruct the experience in your mind that a person would who experienced colour first-hand. Since the meaning and knowledge represented by language are composed of the information present in qualia, you cannot describe the experience of a quale using language.

Apparently Daniel Dennett does not accept the notion that qualia are ineffable. By extension, he must not accept the very existence of qualia. He has asserted that proponents of this thesis never bother to actually present a plausible argument for it. I hereby accept that challenge.

I'm going to take care to describe the attributes of qualia necessary to satisfy the role they fill in this framework. I will demonstrate how they are not a remote and abstract philosophical concept, but rather the bread-and-butter of our every day mental life. Furthermore I will demonstrate that they are indeed ineffable if they have the other attributes I describe.

Qualia defined:

Qualia are atomic units of meaning. They are the fundamental subjective sensations of which all our knowledge of the universe is composed. Here are the properties which a quale must possess to fill this role.

They are subjective:

Qualia are inherently subjective. I don't mean subjectivity in the common sense that "everyone will have their own experience that may vary from others". Rather, I mean that at a fundamental level, the very existence of a quale depends on the subject-object relationship.

Qualia only exist in the event of a juxtaposition of 3 ingredients: a mind, a sense organ, and a physical stimulus to which that sense organ is attuned such as light, sound, heat, etc. This is a significant claim that should require some demonstration:

Our subjective experience of a stimulus is not an intrinsic property of the actual stimulus. Instead it is an emergent artifact of combination of the mind, the sense organs, and the stimulus. The following example demonstrates this. Everyone with normal vision has experienced the subjective sensation of seeing yellow. There is a particular range of the spectrum (570 to 580nm, more or less) which we perceive as yellow. In general, any two people will agree on whether or not something is yellow, so it is fair to say that there is an identifiable subjective experience associated with it. However, the subjective experience is not a property of the light itself. That is why green and red light mixed together will be perceived as yellow. Virtually every colour video display is incapable of producing light in the pure wavelength which we perceive as yellow, yet they can all make you experience the yellow subjective sensation via the colour quale.

This is true of more sensations than you might realize. For example, people will generally report that mint has a "cool" sensation. That is not metaphorical, we actually experience a temperature quale from the chemicals in mint. It is not a "taste", because mint oils rubbed on the skin anywhere on the body will evoke the cools sensation, even though they are incapable of tasting. Likewise, capsicum oil is "hot". In spite of this, if you measure the temperature of these substances, you will not find their actual temperature deviates from the ambient one.

So in a very meaningful way, "red" would not exist in the universe if there were no eyes.

They are Discrete and Indivisible:

There is no perceived relationship between the subjective experience of different qualia. While it is possible for something to be midway between blue and green, it is not possible for something to be midway between F-sharp and salty.

This may seem irrelevant, but it is key to qualia's ineffability. As Hume demonstrated in his "shade of blue" example, people who have experience with colours in general can readily have a sense of adjacent parts of the colour space conveyed to them without direct experience.

I've claimed qualia are atomic. I need to demonstrate this assertion, as it is an important reason for their ineffability. The key to demonstrating this is two-fold: a little biology and a little epistemology.

We have specialized sensors on our body for different qualia. Our brains have specialized innate neural pathways for processing the data from these sensors to produce specific subjective sensations. You don't have to be "taught" to feel cold or see colour, that ability comes naturally.

So our eyes are capable of discerning the colour and intensity of light, our skin can feel temperature, pressure, and pain. We've actually identified specialized nerve cells for these different purposes in some cases. In other cases, very elementary processing in the brain actually isolates different qualia from the input from one type of sensor (for example the pitch and volume of a tone).

The specialized nerve cell in concert with the basic perceptual circuitry to which they directly connect only allow us to perceive specific qualia. When the nerve cells or the brain circuitry to which they connect are artificially stimulated, the result is the perception by the subject of the experiment of the qualia specific to those nerve cells. Therefore heat sensitive cells in our skin can only feel heat, and pressure sensitive cells can only feel pressure. We can, of course, perceive different degrees of heat or pressure, but these are only quantitative differences. There can be no qualitative differences to what is perceived via the specific sensor cells.

Of course, our perception rarely if ever works on a single quale at a time. If we feel a very hot object, both our heat and pain sensors are stimulated, and we perceive that as qualitatively different from a pleasantly warm sensation. That is precisely because different types of sensors are stimulated, and our perceptual processing is combining the information from them.

Furthermore, it is well established that neurons of all types have a stimulation threshold. Below the threshold, the neuron does not "fire", and it is physically impossible for the subject to experience a sensation. Above the threshold the neuron will fire with varying frequency, making it possible for the subject to receive an input of varying intensity.

So, there is a biological reason to believe that there might be discrete and indivisible units of perception which are available to our mind. This also demonstrates that qualia are real, and quite literally tangible. They are not a philosophical artifice. The epistemological perspective bolsters this view.

To reiterate what I said above: information from the universe must enter our mind via our senses. While there is evidence that we have an innate ability to recognize certain higher-order things such as faces, even those facilities are only accessible by stimulation of the senses. At some point between the nuomena of the universe and the higher order conceptual perception of our mind there must exist some perceptual "gateway" which allows us to experience phenomena. The internal conceptual representation of the universe that we store as knowledge simply must be composed of information received via this gateway, as there is no other alternative.

In order for information to be processed effectively by our brain it is critical that we are able to distinguish the different kinds of information. Any ambiguity about whether a particular sensation is, for example, a loud noise or a strong smell would surely reduce the subject's ability to respond appropriately. From this arrises the discrete and indivisible nature of qualia.

So epistemology tells us that there must be a way for information from the "outside world" to reach our mind, and biology tells us that this information arrives as certain discrete sensations. These discrete sensations are combined to produce a unified subjective experience.

The indivisibility of qualia has an important implications for what is and is not a quale. For example, the ability to distinguish colours is a quale, but individual colours are not qualia. Rather individual colours are different "values" which can be attributed to the quale. This is further demonstrated by the fact that a given pixel on a colour screen cannot be perceived as having more than one colour at a time. The simultaneous output of the red, green, and blue sub-pixels are perceived as a single colour until you get close enough to see the sub-pixels themselves. You don't look at a white RGB screen and perceive it as "red and green and blue".

By contrast, the experience of tasting a good wine can be broken down into many individual qualia: There are the sour, bitter, sweet flavours, various aromas of fruit and spice, the tactile sensation from the astringency of the tannins, etc. Therefore the subjective feeling of drinking wine is not a quale, since it is decomposable to other qualia that clearly meet the criteria.

Ineffable:

I don't want to be accused of begging the question, so I won't use this property to prove itself. But as long as I'm listing the properties of qualia, I will include this one. As I've noted, I believe that this property is so fundamental that it is a corollary to their existence.

Proof of ineffability

Armed with the description above, the proof that qualia are ineffable is straight forward. We'll examine the different means by which we could describe the subjective experience of a quale, and demonstrate that the attributes of qualia make each of these means impossible.

First, the fact that they are indivisible means that there is no combination of other units of meaning that can convey the subjective experience of a quale to someone who has not experienced it directly.

Secondly, since they are discrete, there is no way to convey the sensation of one quale by evoking another. One might, for example, say that the colour blue is "cool". However, it is patently obvious that the sense in which this might be true is metaphorical, whereas the coolness of mint is subjectively very closely related to the coolness of ice-cream. These metaphorical descriptions can only be appreciated by someone with direct experience of both the described quale and the metaphorical comparison.

Third, since qualia are subjective, there is no possibility of understanding the first hand experience by analysis of the physical stimulus which causes the sensation. Would any amount of analysis of the colour spectrum yield the expectation that subjectively the combination of red and green light be perceived as yellow? Even more compelling, would you be able to predict that a particular combination of colour frequencies would give rise to the sensation of "white", which is perceived as a unique colour? Surely not, because this property is the result of our perceptual equipment, not of the electro-magnetic noumenon.

Since I have tied qualia directly to well established biological facts, I feel I have credibly demonstrated that such a thing can meaningfully be said to exist. Furthermore, from an epistemological perspective, qualia must exist.

The ineffability of qualia derives directly from the properties which I've ascribed to qualia. I believe I've demonstrated that these properties are not there to support my ineffability case, rather they are fundamental to the nature of the existence of qualia. In addition, I have demonstrated how the properties I've attributed to qualia are grounded in our biology, and our real life experience.

Proving a negative, and a challenge

I've set myself the difficult task of proving a negative. In the strictest sense of the word "proof", I've probably failed to do this. I do think, however, that I've made a compelling demonstration of the fact.

I'd like to challenge those that believe qualia are effable to demonstrate that one person's subjective experience of a quale is the same as (or different from) that of another person. To set the bar even lower: prove that "white" is not actually a unique colour without resorting in anyway to the use of refraction. I believe the ineffability of qualia renders these tasks impossible. However, since that is proving a positive, it should be easily done unless the supposition that qualia are effable is false.